Low LP gain in flex?

Im sure theres a post about this every season but im seeing very strange LP gains, placed in Silver 5 solo/duo, bronze 5 flex - got to bronze 4 very easily after winning probably 7 or 8 of my 10 first games, now in bronze 4 gaing 13 lp/win even though record is 21W-13L where as in solo duo wins net me about 23-25lp. Anyone else experiencing this? is there an explanation?